Pointer behavior in functions in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a pointer to an integer variable.

Go

var x int = 10
var p [1] = &x

Drag options to blanks, or click blank then click option'

Aint

B*int

C&int

Dint*

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of '*int' for pointer type.

Using '&int' which is not a valid type.

Using 'int*' which is not Go syntax.

In Go, a pointer to an int is declared as *int. The & operator gets the address of x.

2fill in blank

medium

Complete the code to modify the value of an integer through a pointer inside a function.

Go

func changeValue(n [1]) {
    *n = 20
}

func main() {
    x := 10
    changeValue(&x)
    fmt.Println(x) // Output: 20
}

Drag options to blanks, or click blank then click option'

A*int

Bint

Cint*

D&int

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of '*int' so the function modifies a copy.

Using invalid pointer syntax like 'int*' or '&int'.

The function parameter must be a pointer to int (*int) to modify the original variable's value.

3fill in blank

hard

Fill both blanks to make the increment function modify x correctly.

Go

func increment(n [1]) {
    (*n)++
}

func main() {
    x := 5
    increment([2]x)
    fmt.Println(x) // Output: 6
}

Drag options to blanks, or click blank then click option'

Aint

B&

C*int

Dpointer

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of '*int' in the function parameter.

Passing 'x' instead of '&x' to the function.

The function parameter must be a pointer to int (*int), and the argument must be the address of x using &x.

4fill in blank

hard

Fill both blanks to create a function that swaps two integers using pointers.

Go

func swap(a, b [1]) {
    temp := *a
    *a = *b
    *b = temp
}

func main() {
    x, y := 1, 2
    swap([2]x, &y)
    fmt.Println(x, y) // Output: 2 1
}

Drag options to blanks, or click blank then click option'

A*int

B&

Cint

Dpointer

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of '*int' for parameters.

Passing variables directly instead of their addresses.

The function parameters must be pointers to int (*int), and the arguments must be addresses of variables using &.

5fill in blank

hard

Fill all three blanks to create a function that doubles the value of an integer using a pointer and returns the new value.

Go

func doubleValue(n [1]) [2] {
    *n = *n * 2
    return [3]
}

func main() {
    x := 7
    result := doubleValue(&x)
    fmt.Println(result, x) // Output: 14 14
}

Drag options to blanks, or click blank then click option'

A*int

Bint

C*n

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of '*int' for the parameter.

Returning the pointer variable instead of the dereferenced value.

Using wrong return type.

The function parameter is a pointer to int (*int), the return type is int, and the function returns the dereferenced value *n.